Prior attempts to fabricate a microchip or microsensor assemblies that could survive for long periods of time in saline or high humidity environments have failed due to a number of factors. This challenge is particularly critical in implantable medical devices.
This challenge has been met in the case of implantable heart devices by providing core electronics and all controller chips in a “pacemaker can”, which is located outside the heart. This relatively large device allows the full hermeticity protection of core electrical components. However, its size precludes the use of this protection at a site within the heart. This limitation has challenged development of cardiac devices which can provide microprocessing at the site of the sensing or actuation.
Important avenues of medical device development would be opened if an on-site packaging would become available which would protect key electrical, mechanical and/or actuation components from the effects of leakage of local materials into the devices.